The scene above is from Dinosaur National Monument and features a view of the Green River emerging from Split Mountain. The meandering Green River is, in this case, an example of an antecedent drainage that has cut down through the uplifting sedimentary layers quickly enough to keep pace with the uplift and folding of those layers during the Laramide Orogeny a superposed drainage which has recently cut down through the rocks earlier folded as part of the Sevier and Laramide Orogenies [correction based on Wayne’s comment below]. The prominent cliff former that forms the bulk of Split Mountain is the Middle Pennsylvanian to Lower Permian Weber Sandstone. Hogbacks of the yellow and red Lower Permian Park City Formation lap onto the south side of the Weber like waves breaking on a beach. The red siltstones of the Lower Triassic Moenkopi Formation form a strike valley at the right of the image – to the west this strike valley is known as the Racetrack as it wraps around the nose of the plunging Split Mountain Anticline.